Hi everyone, Monica Reinagel, the nutrition diva here, with this week's quick and dirty tips for eating well and feeling fabulous.

How long would you have to exercise to burn off the calories in your

lunch today? A new study suggests that knowing the answer to that might motivate you to

eat healthier. The photograph of the pizza looks

delicious, bubbling with cheese and studded with pepperoni, but then you

see the caption. A hundred and sixty five pound woman has to jump rope for

45 minutes to burn off the calories in two pieces of pepperoni pizza. And then there are four more slides showing similarly

decadent foods and then the exertions required to negate their calorie content.

These arresting images accompanied CNN.com's coverage of a study recently published in the American

Journal of Public Health. And as CNN reported, quote, the number of calories and a food or

beverage item doesn't mean much to many folks, but showing

people how much activity they would have to do to burn those calories off might be enough

to convince us to ditch our unhealthy habits."

It was a good news hook and that story got a lot of play.

And some commentators joked that we should maybe replace the calories on the nutrition facts label

with the miles you'd need to run to burn that food off.

Although this might actually be motivating for some people, I'm not crazy about this approach.

And first, let me just give you a word or two about the study that prompted CNN's piece.

Researchers from Johns Hopkins University

tested the impact of various kinds of calorie messaging on teenagers who were buying

sodas after school at corner stores in low-income neighborhoods in Baltimore.

In other words, this was a very specific population in a very specific environment.

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